//
// Created by hsj on 2024-1-11.
// 多播基于UDP;多播组是D类IP地址( 224.0.0.0~ -239.255.255.255 )
// D类地址224.x.x.x~239.x.x.x

#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <fcntl.h>

#ifdef WIN32
//windows minGW64
//inet_pton函数：_WIN32_WINNT
#ifdef _WIN32_WINNT
#undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0600
#include <winsock2.h>
#include <ws2tcpip.h>
//#pragma comment(lib,"ws2_32.lib")
#else
//linux  gcc
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/select.h>
#endif
#define TTL 64
#define BUF_SIZE 30
void error_handling(char *buf);
int main(int argc,char *argv[]){
    int send_sock;
    struct sockaddr_in mul_adr;
    int time_live=TTL;
    FILE *fp;
    char buf[BUF_SIZE] ;
    char ip[]="224.1.1.2";
    char port[]="3344";

    send_sock=socket(PF_INET, SOCK_DGRAM, 0);
    memset(&mul_adr, 0, sizeof(mul_adr));
    mul_adr.sin_family=AF_INET ;
    mul_adr.sin_addr.s_addr=inet_addr(/*argv[1]*/ip);// Multicast IP
    mul_adr.sin_port=htons(atoi(/*argv[2]*/port));// Multicast Port
    setsockopt(send_sock, IPPROTO_IP,
            IP_MULTICAST_TTL, (void*)&time_live, sizeof(time_live));
    if((fp=fopen("news.txt", "r"))==NULL)
        error_handling("fopen() error");

    while(!feof(fp))/* Broadcasting */
    {
        fgets(buf, BUF_SIZE, fp);
        printf("%s\n",buf);
        sendto(send_sock, buf, strlen(buf),0, (struct sockaddr* )&mul_adr, sizeof(mul_adr));
        sleep(2);//sleep 2 sec
    }
    fclose(fp);
    close(send_sock);

    return EXIT_SUCCESS;
}

void error_handling( char *message){
    fputs (message, stderr);
    fputc('\n', stderr);
    exit(1);
}